31990213 has 4 divisors (see below), whose sum is σ = 32532480. Its totient is φ = 31447948.

The previous prime is 31990199. The next prime is 31990229. The reversal of 31990213 is 31209913.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 31990213 - 2⁹ = 31989701 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31990313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 271045 + ... + 271162.

It is an arithmetic number, because the mean of its divisors is an integer number (8133120).

Almost surely, 2^31990213 is an apocalyptic number.

It is an amenable number.

31990213 is a deficient number, since it is larger than the sum of its proper divisors (542267).

31990213 is an equidigital number, since it uses as much as digits as its factorization.

31990213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 542266.

The product of its (nonzero) digits is 1458, while the sum is 28.

The square root of 31990213 is about 5655.9891265808. The cubic root of 31990213 is about 317.4478406474.

The spelling of 31990213 in words is "thirty-one million, nine hundred ninety thousand, two hundred thirteen".